Medical sheet and method of manufacture

ABSTRACT

A cover sheet for medical tables, beds or gurneys comprises a sheet formed from a high tensile strength, plastic with opposed ends of the sheet folded and seamed to provide pockets. The pockets are inverted for assemblage over the ends of the medical tables, beds or gurneys. Methods of continuously fabricating such cover sheets from a roll of plastic material are also disclosed.

This application is a division of application Ser. No. 07/667,424, filedMar. 11, 1991 now U.S. Pat. No. 5,227,218.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to a protective cover sheet for isolation of thebody of a patient from a support surface provided by an examinationtable, a hospital bed or a portable gurney, and to a method ofmanufacturing such cover sheet.

2. Summary of the Prior Art

Every medical doctor's office has an examining table of elongated,generally rectangular configuration upon which successive patientsgenerally end up in a reclining position. In the same manner, hospitalsand emergency vehicles are equipped with portable gurneys on which aninjured or a seriously ill patient is supported for transport. Hospitalbeds require frequent changes of the bottom sheet. In all such cases, itis highly desirable that the patient supporting surface of the bed,examining table or the gurney, as the case may be, be protected fromcontact with patient bodily fluids by a cover sheet. In many cases, andparticularly in doctor's offices, the cover sheet is an ordinary sheetof paper. In hospitals, the cover sheet may be formed of cloth and hencemust be washed and sterilized for reuse. Similar problems may beencountered in the home due to incontinence or diarrhea.

In any case, the existence of an economical, disposable, biodegradablecover sheet that is fitted to the patient supporting surface so as tooverlie all of the surface and the adjoining edges, is lacking.Moreover, in many cases, the cover sheet is highly permeable to bodyfluids, resulting in contamination of the patient supporting surface ofthe bed, examining table or gurney, requiring cleaning and sterilizationof such surface.

A problem is also encountered, particularly in emergency vehicles andhospitals, in transferring the body of an injured or a seriously illpatient from the gurney to a hospital bed or operating table. With thecurrent Aids epidemic, the personnel handling the patient are at risk bycontact with the patient's bodily fluids if they physically grasp thepatient. It would be highly desirable that the cover sheet be fabricatedof such material as to not only be highly impermeable to body fluids butalso to have sufficient tensile strength to permit the body of thepatient to be lifted and moved simply by grasping the edges of the coversheet. Lastly, the cover sheet should fit snugly on the patientsupporting surface and should be disposable and biodegradable.

A cover sheet having these properties is not believed to have heretoforebeen disclosed in the prior art. U.S. Pat. No. 3,956,782 discusses thedisadvantages of muslin sheets, but discloses a plastic cover sheethaving pockets extending along each longitudinal edge that cannot besnugly fitted around the transverse ends of the patient support surface.

SUMMARY OF THE INVENTION

A cover sheet for isolation of the body of a patient from an elongatedsupport surface of a generally rectangular configuration comprises asheet formed of a specialized biodegradable plastic material having hightensile strength, high resistance to fluid penetration, and shaped toextend perimetrically beyond the elongated side and the end portions ofthe support surface. The end portions of such sheet which extend beyondthe support surface are folded in such manner as to define pockets torespectively snugly surround the ends of the elongated patient supportsurface.

In a preferred embodiment of the invention, the pockets are formed byreversely, transversely folding the excess end portions to lie adjacentthe under surface of the patient support surface. That portion of thereversely folded end portion which is intermediate the top end surfaceof the patient support and the reverse fold is then provided with atransverse reentrant folded portion. The total width of the re-entrantfolded portion, when unfolded, is slightly greater than the thickness ofthe support surface for which the protective cover sheet is designed.Whether the reverse fold is formed prior to, or after the formation ofthe re-entrant folded portion is immaterial.

When such folded portions have been formed, they are compressed againstthe adjacent portions of the cover sheet and a longitudinally extending,linear securement of both folded portions to the isolation sheet isformed, either by stitching, a linear heat seal, or through theapplication of lines of adhesive to those portions of the plastic sheetthat are to be secured together. Thus a protective sheet cover is formedhaving the same general dimensions as the patient support surface andhaving pockets formed in each end to snugly surround the cantileveredend portions of the patient support surface.

In a preferred embodiment of the invention, the pockets formed in themanner described above are then inverted before application to thepatient support surface. The inversion action places those longitudinaledge portions of the sheet which are secured together within theinterior of the pocket, rather than projecting exteriorly of the pocketwhen applied to the patient support surface. The additional advantage ofinverting the pockets is that a downward bias is then imparted to theexcess width portions of the protective sheet cover causing them todrape downwardly adjacent the longitudinal edges of the patient supportsurface. In this manner, a very neat appearance of the sheet as appliedto the patient support surface is achieved.

The manufacture of a protective sheet embodying this invention can bereadily accomplished by a series of manual operations on a single sheetof plastic material, or can be accomplished by an automatic operationwherein sheet plastic is withdrawn from a roll of such plastic sheet.The withdrawn plastic sheet is of a width substantially in excess of thelength of the patient support surface for which the protective sheet isbeing manufactured. As the sheet is withdrawn, folding apparatus, of atype well known in the art, is applied to both lateral edges of thewithdrawn sheet to form in such lateral edges both the reentrant foldpreviously described and the reverse fold.

The folded sheet then passes a securement mechanism which applies eithera longitudinal stitching, a longitudinal line of adhesive, or a linearheat seal to the edges of the folded sheet to effect the linearsecurement of the outer ends of the folded portions to the main body ofthe sheet. The continuous sheet is then transversely severed adjacentthe linearly secured portions to provide sheet width corresponding tothat desired for the particular patient supporting surface, with eachsevered width having a flat configuration for packaging but havingflattened tansverse pockets formed at each end for respectively snuglyengaging the ends of the elongated patient support surface, particularlywhen the pockets are inverted.

Further advantages of the apparatus and method inventions disclosed inthis application will be readily apparent to those skilled in the artfrom the following detailed description, taken in conjunction with theannexed sheets of drawings, on which are shown several preferredembodiments of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a cover sheet for a patient supportsurface as such sheet is initially formed.

FIG. 2 is an enlarged scale sectional view taken on the plane 2--2 ofFIG. 1.

FIG. 3 is an enlarged scale partial sectional view taken on the plane3--3 of FIG. 1.

FIG. 4 is an elevational view of the cover sheet prior to the foldingoperations indicated by dotted lines.

FIG. 5 is a schematic block diagram illustrating the steps involved infabricating by hand a cover sheet embodying this invention.

FIG. 6 is a schematic block diagram illustrating a preferred method offabricating a cover sheet embodying this invention by a continuousmachine process.

FIG. 7 is a perspective view of the cover sheet embodying this inventionwhen the end portions thereof are inverted and the cover is applied to apatient supporting surface.

DESCRIPTION OF PREFERRED EMBODIMENT

Referring to FIG. 1, there is shown a perspective view of a protectivecover sheet 10 embodying this invention in the form in which it isoriginally manufactured, but not in the form in which it is applied to apatient supporting surface of an examining table, bed, or gurney. Asmanufactured, the cover sheet 10 is of elongated rectangularconstruction and having a length dimension greater than the lengthdimension of the patient supporting surface to which it is to beapplied, and, a similarly determined width dimension. Each longitudinalend of cover sheet 10 has a re-entrant folded portion 10a formedthereon. The total width of the re-entrant portion 10a, when unfolded,is substantially equal to, but not less than the thickness of thepatient supporting surface. The bottom edge of each re-entrant portion10a is reversely folded to form an end portion 10b. Both re-entrantfolded portions 10a and the reversely folded end portions 10b lie snuglyagainst the underside of the cover sheet 10 as originally manufactured,as is better shown in FIGS. 2 and 3.

Adjacent the longitudinal edges of the cover sheet 10, stitching 12 orother form of longitudinal securement is provided which effects thelinear longitudinal securement of both the re-entrant portions 10a, andthe reversely folded portions 10b to the main body portion of the coversheet 10. Such linear longitudinal securement may be effected by alongitudinal heat seal, or by the application of lines of adhesive tothe abuttable surfaces of the bottom surface of the cover sheet 10, there-entrant folded portions 10a and the reversely folded portions 10b.

The width separation of the stitching 12 is slightly greater than thewidth of the patient support surface for which cover 10 is designed.Thus, pockets are defined on each end of the sheet which will snuglyreceive the ends of the patient support surface.

Referring to FIG. 4, which is a dimensional drawing, there is shown acover sheet 10 designed for application to a patient supporting surfacehaving a length of 72 inches and a width of 22 inches. Thus the initiallength of the cover sheet 10 is preferably approximately 90 inches inlength. Assuming that the thickness of the patient supporting surface is4 inches, the reversely folded portions 10a are each 2 inches in width,given a total unfolded width of 4 inches. The reversely folded portion10b may be of any convenient length, preferably greater than that of there-entrant folded portions 10a and here shown as being 51/2 inches. Thewidth of the cover sheet 10 is approximately 8 inches greater than thepatient supporting surface to which it is to be applied.

The locations of the folds which form the re-entrant folded portion 10aand the reversely folded portion 10b are indicated by the transversedotted lines.

Referring now to FIG. 7, the cover sheet 10 is shown as applied to thepatient supporting surface (not shown) of a portable gurney 20. Beforeapplying the cover sheet 10 to the patient supporting surface, both ofthe folded ends are inverted, thus placing the tabs 10c, which extendlaterally beyond the stitching 12 or other form of longitudinalsecurement illustrated in FIG. 1, within the confines of the respectivefolded end portion which then defines a pocket to snugly receive therespective end portion of the patient supporting surface of the gurney20.

The cover sheet 10 is preferably formed from a plastic material havingboth high tensile strength and high resistance to fluid permeation. Aplastic sheet having these properties, yet being economical enough towarrant use as a disposable cover sheet comprises a polypropylene sheetformed by the so-called spun bonded process wherein a plurality ofpolpropylene fibers are laid on a mat and then heated and compressed toform a substantially impervious sheet. This type of sheet is known inthe art and may be obtained from a number of suppliers of polypropylenesheet. A preferred density or weight of such sheet is in the range of1.25 to 2.00 ounces per square yard. Preferably, a sheet having a weightof about 1.6 ounces per square yard is employed. This sheet has a grabtensile resistance in the machine direction of 107.8 lbs. and in thecross direction, 58.8 lbs. It's grab elongation in the machine directionis 43.6% and in the cross direction 53.1%. No chemical binders areemployed in the fabrication of such sheet. Its strength is in no manneraffected by contact with fluids and it is highly resistant to fluidpermeation.

A sheet having these properties has sufficient strength that an averagesize patient lying on the sheet may be bodily lifted by merely graspingthe edges of the sheet, eliminating any contact with the body of thepatient.

Referring now to FIGS. 5 and 6, there is indicated by block diagrams twomethods of forming a cover sheet embodying this invention. The firstmethod illustrated by the blocks in FIG. 5 has already been described.

A preferred method for producing large quantities of covers by asubstantially continuous process is illustrated by the block diagram ofFIG. 6. In this method, the polypropylene sheet is obtained on rollshaving a width equal to the desired length of the sheet for applicationto a particular patient supporting surface. Thus, using the example ofFIG. 4, the width of the continuous sheet on the roll would be 90 inchesand this large width sheet is continuously withdrawn from the roll.

Due to the fact that the longitudinal edges of this wide sheet willbecome the transverse edges of the cover sheet, the re-entrant fold andthe reverse folds may be continuously formed in the longitudinal edgesof the wide sheet. Such folding operations are performed by apparatusthat is entirely conventional in the art.

Having achieved the two folding operations, and effecting the flatteningof the folded portions of the sheets, the sheet is then passed throughtwo seaming apparatuses respectively located at each side of the widesheet. These seaming apparatuses are well known in the art and aresynchronously operated with the movement of the sheet to produce theseams 12 shown in FIG. 1.

After the seams 12 have been produced, conventional cutting apparatus isemployed to cut the wide sheet transversely to produce a sheet form 10identical to that shown in FIG. 1. Obviously, the cutting is performedoutside of each of the seams 12.

With the aforedescribed method, cover sheets may be continuously andautomatically produced, thus greatly reducing the manufacturing costs ofsuch sheets and making the sheets very attractive to hospitals anddoctors as a biodegradable, disposable item.

Those skilled in the art will recognize that the cover sheetconstruction, and the methods of fabricating same heretofore described,represent a significant advance in the field of protective covers forany patient supporting surface. Obviously, cover sheets may be made inlarger configurations so as to fit hospital beds and beds employed inthe home. In the latter case, illnesses such as incontinence anddiarrhea may makes the employment of a substantially fluid impermeablesheet highly desirable to protect the mattress upon which the patient isresting.

What is claimed and desired to be secured by Letters Patent is:
 1. Apatient support apparatus for use with a patient support surfacecomprising:a sheet being fabricated from spun bonded polypropylene andoriginally sized and shaped to extend at least to a perimeter of thepatient support surface; the sheet having high resistance to fluidpenetration in order to protect the patient support surface from contactfrom bodily fluids of a patient; the sheet further having high tensilestrength to allow lifting of the patient by grasping edges of the sheet;and the sheet further includes end pocket portions for snugly receivingthe transverse end portions of the patient support surface.
 2. Theapparatus of claim 1 wherein the pockets are formed from end portions ofthe sheet reversely folded to form reverse folds, each reverse foldhaving lateral edge portions secured to an adjacent sheet portion bylongitudinal seams.